By Ramona Young-Grindle
The U.S. Fish and Wildlife Service has listed six invertebrates in west Texas as endangered under the Endangered Species Act, and designated 450 acres of critical habitat for the rare freshwater shrimp and snails, in separate actions. The agency also changed the common names of the four snails to conform to standardized English names for North American mollusks, according to the listing.
The USFWS proposed listing the six species last year in response to a 2011 settlement with the Center for Biological Diversity (CBD), a conservation group that had petitioned to have the species protected in 2004. "The animals have been on the waiting list for federal protection for many years," the CBD said. Two of the snails had previously been proposed for listing in 1976, listingg was prthe two shrimp, or amphipods, were proposed in 1984, and the other two snails were proposed in 1989, according to the CBD's statement. The 2011 settlement between the USFWS and the CBD resulted in an agreement to speed listing decisions for 757 species across the country.
The six aquatic species are found in only two spring systems, the San Solomon Spring and Diamond Y Spring, both in the Chihuahuan Desert. The spring-adapted species probably evolved from parent populations that were more widely distributed during the wetter, cooler climates of the Pleistocene epoch, from 10,000 to 2.5 million years ago. As the region became drier over the last 100,000 years, the populations of aquatic species became geographically isolated, according to the listing action.
"The natural spring systems that support the six aquatic invertebrates are declining, in both quantity and quality. The degradation and loss of these natural springs is not just a problem for the species dependent upon them but may also affect the water supplies of local communities," Adam Zerrenner, the USFWS' Austin Field Office Supervisor was quoted as saying in the agency's press release. More....